Gas burner



Nov. 15, 1960 w, DOLBY 2,960,157

GAS BURNER Filed Nov. 29, 1955 FIGZ . INVENTOR.

John W Dolby WZj 342107776175 GAS BURNER John W. Dolby, Elgin, Ill.,assignor to Configured Tube Products $0., Bellwood, [1]., a corporationof Illinois Filed Nov. 29, 1955, Ser. No. 549,662

Claims. (Cl. 158116) This invention relates to burners for use with amixture of gaseous fuel and air and pertains particularly to burnersmade of sheet metal or the like.

Thus, one principal object of the invention is to pro vide a new andimproved burner which may be made very economically, principally ofsheet metal or other thin material, yet will give outstandingperformance when used on a cooking stove or some other heatingappliance.

A further object is to provide a burner of the foregoing character whichis extremely small in size yet is capable of adequately high heatoutput.

It is another object to provide a new and improved burner which willprovide heat output over an extremely wide range so that the burner maybe adjusted to the slowest simmer or the fastest boil or to any desiredheat setting therebetween.

A further object is to provide a new and improved burner of theforegoing character which is arranged to prevent the burner flame frombackfiring into the burner.

It is another object to provide a new and improved burner of theforegoing character which is arranged to provide an advantageous flamedistribution.

Further objects and advantages of the invention will appear from thefollowing description, taken with the accompanying drawings, in which:

Figure 1 is an enlarged elevational view of a sheet metal burnerconstituting an illustrative embodiment of the present invention;

Fig. 2 is a central elevational sectional view taken through the burnerof Fig. 1; and

Fig. 3 is a plan view of the burner of Fig. 1.

If the drawings are considered in greater detail, it will be seen thatthey illustrate a burner which is shown at about twice its actual size.It will thus beappreciated that the burner is of extremely compact form.Nevertheless, the burner is capable of being adjusted continuously togive a heat output over an extremely wide range extending, for example,between 500 and 16,000 B.t.u.s per hour.

The illustrated burner is made principally of sheet met al and hence maybe produced at extremely low cost. The small size of the burner alsocontributes to its economical construction. It will be seen that theillustrated burner 19 comprises an outer shell 12, generally of invertedcup-shaped form. As shown, the outer shell 12 comprises a two-diameterside wall 14 surmounted by a flat horizontal top wa1l16. The lower endof the shell is formed into a mounting flange 18 which surrounds anaxial opening 20- adapted to receive a mixture of fuel and air from asuitable mixing tube or the like. The burner is constructedfor use withall city gases, whether natural, manufactured or mixed, and also for usewith liquified petroleum gases including butane and propane.

The illustrated two-diameter side wall 14 comprises a lower portion 22of relatively large diameter and an up per portion 24 of smallerdiameter. An annular, sub- States Patent stantially horizontal shoulderor step 26 is formed between the lower and upper portions 22 and 24.

To discharge the fuel and air mixture from the shell 12, a multiplicityof main ports '28 are formed through the upper, small diameter portion24. All of the ports 28 are at the same horizontal level and are spacedat short distance above the shoulder 26. The relation between theshoulder or olfset portion 26 and the ports 28 is such that at low turndown the shoulder forms a pocket which causes the fire from the ports tomerge creating, in eifect, a single annular port. This action results instable operation of the burner at extremely low flow rates.

A multiplicity of secondary ports 30 are formed in the larger diameterportion 22 of the outer shell 12. It Will be seen that the diameter ofthe secondary ports. is substantially less than that of the primary ormain ports 28. The secondary ports 30 are spaced a short distance belowthe shoulder or step 26.

The flow of fuel-air mixture to the secondary ports 39 is controlled bya generally tubular baflle 32 mounted within the outer shell 12. It willbe seen that the tubular bafiie 32 takes the form of a three-diameterinner shell having an upper annular element 34 of relatively smalldiameter, a lower element 36 of relatively great diameter, and anintermediate annular element 38 of intermediate diameter. A pair ofshoulders or steps 40 and 42 are formed between the intermediate element33 and the upper and lower elements 34 and 36.

As illustrated, the upper element 34 is of an outer diametercorresponding to the inner diameter of the smaller portion 24 on theouter shell 12. The element 34 is snugly received within the lower endof the portion 24 so that a gas-tight joint will be formed therebetween.The upper side of the step 40 abuts against the lower side of the stepor shoulder 26 so that the inner shell 32 is positively located in theouter shell 12. As shown, the small diameter element 34 has an upper,substantially horizontal annular edge 44 which is adjacent the lowermargins of the main ports 28. The inner shell 32 thereby convenientlyprovides an inwardly extending annular ledge at a level correspondinggenerally to that of the lowermost extremities of the ports 28. Theannular ledge or edge 44, when located as shown in Fig. 2, tends to havea lowering or depressing effect on the path of the fuel-air mixture asit passes outwardly through the ports 28, so that the mixture travelsoutwardly at a smaller upward angle than it would in the absence of theledge 44.

The width and elevation of the ledge 44 affect the angle of the flame.In general, the lowering effect on the flame tends to be increased asthe ledge 44 is made higher relative to the lower'extremities of theports 28. In other words, raising the ledge increases the lowering ordepressing effect on the flame.

It will be seen that the large diameter lower element 36 of the innershell 32 corresponds in outer diameter to the inner diameter of thelower portion 22 on the outer shell 12. The portion 36 is snuglyreceived within the portion 32 so as to form a gas-tight jointtherebetween. The inner shell 36 may be secured within the outer shell12 in any suitable manner, as by spot or seam Welding, as indicated at48 in Fig.2.

The intermediate portion 38 of the inner shell 32 is of an outsidediameter greater than that of the smaller portion 34 but less than theinside diameter of the lower portion 22 on the outer shell 12. Thus, anannular space 50 is defined between the intermediate portion 38 and thecylindrical portion 22 of the outer shell 12. A plurality of meteringports 52 extend through the intermediate portion 38 to admit thefuel-air mixture to the space 50. It will be seen that the meteringports 52 are small in size and few in number so as to restrict the flowof mixture into the space 50. The metering ports 52 are at asubstantially lower level than that of the secondary discharge ports 30.The arrangement ofthe wall portions 22 and 38 and the ports 30 and 52 issuch as to prevent backfiring through the secondary ports 30. If anyflame travels back through one of the ports 30, it will be extinguishedby the cool inner wall portion 38 and will not be propagated through thespace 50 into the interior of the shells 12 and 32. The provision of thespace 50 and the arrangement of the ports 30 and 52 stabilizes theflames at the secondary ports 30. The flames at the secondary portsstabilize the main flames at the main ports 28, particularly at highrates of flow. In particular, the secondary flames prevent the mainflames from being blown away from the main ports 28.

To direct the fuel-air mixture through the main ports 28 and preventbackfiring therethrough, the burner is provided with an additionalbaifling member 54 which may assume various forms, but, as shown, isgenerally of inverted cup-shaped form. Thus, the baffle 54 comprises afiat substantially horizontal upper wall 56 which is secured to theunderside of the top wall 16 on the outer shell 12. One or more spotwelds 58 may be formed between the walls 16 and 56 to hold the baffle 54in place. The baflle 54 also includes an annular, substantiallycylindrical side wall or flame 60 which extends downwardly in dependingrelation to the upper wall 56. It will be seen that the annular sidewall 60 is concentric with but spaced inwardly from the upper side wallportion 24 on the outer shell 12. The annular wall 60 extends downwardlyso that it will at least partly overlap the main ports 28. It will beunderstood that the exact level of the edge 62 may be varied to acertain extent, with some effect upon the angle of the flames at theports 28. As illustrated in Fig. 2, the spacing between the baffle wall60 and the wall 24 of the shell 12 is comparable to the size of the mainports 28, and is a minor fraction of the diameter of the baflle.

The annular baflle wall 60 substantially prevents backfiring of theflames through the ports 28. If any flame travels inwardly through oneof the ports 28, it will be extinguished by the cool depending flange60. Thus, the flame will not be propagated into the interior of theouter shell 12. The ledge 44 and the depending flange 60 cooperate toincrease the efiective depth of the main ports 28.

Another important effect of the baflle 54 is to regulate the directionor angularity of the flames at the main ports 28. Generally, the loweredges of the baffle 54 cooperate with the upper extremities of the mainports 28 to determine the angularity of the upper portions of the mainflames. Thus, varying the elevation of the lower edges of the baflie 54will change the angle of the flames. Lowering the lower edge of thebaflle will tend to deflect the flames upwardly so that they will make ahigher angle to the horizontal. On the other hand, raising the lowerextremity of the baffle will tend to lower the angle of the flames.

Thus, the direction of the flames at the main ports 28 can be varied toa considerable extent by changing the elevation of the lower edge of thebaffle 54 and the upper edge 44 of the baffle element 34. In theillustrated construction, the upper edge or ledge 44 is at substantiallythe same elevation as the lower extremities of the main ports 28. Thelower edge 62 of the bafile 54 extends downwardly below the elevation ofthe upper extremities of the ports 28 and generally is at the elevationof the axes of the ports. This arrangement results in main flames whichare directed upwardly at a small angle to the horizontal and tend tocurl upwardly as they travel outwardly. The general shape of the flameis indicated by a flame pattern 64 in Fig. 2.

To spread the flames and control this upward curling eflect, the burneris provided with a flame spreader 66 mounted on the top of the outershell 12. While the flame spreader 66 might readily be made in onepiece, it is made in lower and upper parts 68 and 69 in the illustratedconstruction. It will be seen that the lower part 68 is made of sheetmetal and is generally cup or disk shaped. It has a lower wall 70 whichis welded or otherwise secured to the upper wall 16 of the outer shell12. The diameter of the lower wall 70 corresponds roughly but isillustrated as being slightly less than that of the wall 16. Adownwardly tapering frusto-conical side wall 72 extends upwardly fromthe lower wall 7 0.

In this instance, the upper part 69 of the flame spreader 66 is in theform of a disk-like member having an upper portion 74 which is supportedon the upper edge of the side wall 72 and projects outwardly inoverhanging fashion therefrom. As illustrated, the disk-like part 69 hasa downwardly projecting lower portion 76 which is received in the upperend of the disk-shaped lower part 68. It will be seen that theprojecting lower portion 76 is downwardly tapered in conformity with theshape of the side wall 72. As illustrated, the upper part 69 is merelyretained by gravity in the lower part 68, but, of course, the two partsmay be suitably welded or otherwise secured together.

The upwardly flaring side wall 72 and the overhanging portion 74 of thedisk 69 tend to spread the main flames outwardly so that they willengage a large area on any kettle or pot placed above the burner.

When there is no cooking utensil over the burner, the action of theflame spreader 66 is particularly important in controlling the upwardcurl of the main flames. With a large kettle or pan over the burner, thebottom of the pan directs the flames outwardly so that they travel alonga maximum area on the pan. Thus, the pan has a spreading effect on theflame. In other words, the flames tend to change in shape to adaptthemselves to the size and shape of the pan.

When the burner is turned on to extremely low levels, the spreader 66spreads the heat from the flames outwardly so that the heat is directedto the outer edges of the pan and is not concentrated at the center.This arrangement prevents scorching of food at low levels of heatoutput. With the present burner, it is thereby possible to cook foods atlow turn down directly over the flame rather than using a double boiler.

While the operation of the burner has already been completely described,it may be helpful to offer a brief summary. At high rates of fuel flowthrough the burner 10, both the main ports 28 and the secondary ports 30support flames. The ledge 44 and the lower edge 62 of the baflie 54cooperate to direct the main flames upwardly and outwardly from the mainports 28 at an angle to the horizontal. The outer ends of the mainflames tend to curl upwardly, but this curling eflect is controlled bythe flame spreader 66. When there is no pan or the like over the burner,the flame spreader 66 has its maximum effect. The apparatus of the mainflames is greatly improved by the flame spreader. With a small pan overthe burner, the flame spreader 66 directs the flames outwardly so thatthey will engage the outer portions of the pan. Larger pans, when placedover the burner, have a further spreading eflect, with the result thatthe flames travel outwardly along the bottom of the pan and therebyengage a maximum area on the pan. At low turn downs, the flame spreaderdistributes the heat from the burner and prevents scorching of food.

At high rates of fuel flow, a separate flame is maintained at each ofthe main ports 28. The maximum heat output of the burner is adequatelycorrect for any cooking operation such as rapidly bringing water to aboil. For example, a heat output of 16,000 B.t.u.s is readily obtained.

As the rate of fuel flow is turned down, the size of the flames at theports 28 is decreased until all of the main flames-eventuallymerge intoa single ring of flame encircling the ports 28. Thus, the main ports 28.effectively constitute a single annular port at low rates of flow. Inthis way, the operation of the burner is greatly stabilized at lowlevels. At the minimum rate of fuel flow, the flames at the secondaryports 30 will go out. Any small amount of fuel that may issue from thesecondary ports will be consumed in the flame at the main ports.

It will be apparent that a substantially continuous rate of heat outputis obtained between extremely high and extremely low levels. The flameat the main ports is maintained in a stable condition downto a flow rateof 500 B.t.u.s per hour, for example. The burner may be adjusted to anextremely high level to bring water to a boil, an extremely low levelfor keeping food warm or directly cooking easily scorched foods normallyrequiring the use of a double boiler, or to any intermediate level suchas one suitable for frying. Backfiring of the flames through the mainports 28 is prevented by the baffle 54 which cools and therebyextinguishes any flame that may travel inwardly through the ports 28.

Since the burner is, made principally of sheet metal and is of extremelysmall size, it is unusually economical in construction. Nevertheless,its performance on a cooking stove is outstanding in every way,particularly with regard to maximum heat output, minimum heat output andthe continuity of the intermediate range of heat outputs.

Various modifications, alternative constructions and equivalents may beemployed without departing from the true spirit and scope of theinvention as exemplified in the foregoing description and defined in thefollowing claims.

-I claim:

1. In a burner, the combination comprising an outer shell having agenerally annular side wall surmounted by a top wall, said side wallhaving an upper portion of relatively small diameter and a lower portionof greater diameter with a shoulder therebetween, a plurality ofangularly spaced main ports extending through said upper portion, aplurality of angularly spaced secondary ports extending through saidlower portion, a generally tubular inner shell received within saidouter shell, said inner shell including an upper relatively smalldiameter element, a lower relatively large diameter element, and anintermediate element therebetween, said upper element being snuglyreceived within said upper portion and having an upper bafliing edgeportion adjacent the lower margins of said main ports, said lowerelement being snugly received within said lower portion substantiallybelow said secondary ports, said intermediate element being spacedinwardly from said lower portion and thereby being effective to definean annular space therebetween, said secondary ports communicating withsaid annular space, a plurality of spaced ports ex tending through saidintermediate element and communieating with said space, and a generallycylindrical annular baflle dependingly mount-ed on said top wall ininwardly spaced relation to said upper portion, the spacing between saidbafiie and said upper portion being a minor fraction of the diameter ofsaid baffle, said annular baffle having a lower edge portion generallyat the level of said main ports and in inwardly spaced relation theretoto prevent backfiring through said ports.

2. In a burner, the combination comprising an outer generally invertedcup-shaped shell having an annular side wall surmounted by a top wall,said side wall having an upper portion of relatively small diameter anda lower portion of greater diameter with a shoulder therebetween, aplurality of angularly spaced main ports extending through said upperportion at a level above said shoulder, a plurality of angularly spacedsecondary ports extending through said lower portion at a level belowsaidshoulder, a generallytubular inner shell re' ceived within saidouter shell, said inner shell including an upper relatively smalldiameter element, a lower relatively large diameter element, and anintermediate element of intermediate diameter, said upper element beingsnugly received within said upper portion and having an upper bafflingedge adjacent the lower margins of said main ports, said lower elementbeing snugly received within said lower portion substantially below saidsecondary ports, said intermediate element being substantiallyconcentric with but spaced inwardly from said lower portion and thererbybeing effective to define an annular space therebetween, said secondaryports communicating with said annular space, a plurality of angularlyspaced metering ports extending through said intermediate element andcommunicating with said space, an annular generally cylindrical bafiedependingly mounted on said top wall in concentric and inwardly spacedrelation to said upper portion, the spacing between said baflie and saidupper portion being a minor fraction of the diameter of said baffle,said annular baffle having a lower edge portion partly overlapping saidmain ports in inwardly spaced relation thereto to prevent backfiringthrough said main ports, and an upwardly flaring flame spreading memberfixed on said top wall.

3. In a burner, the combination comprising an outer shell generallyofinverted cup-shaped form and having an opening for receiving a.mixture of fuel and air, said outer shell having a side wall surmountedby a top wall, saidside wall including a lower generally cylindricalrelatively large diameter portion and an upper generally cylindricalrelatively small diameter portion with an annular shoulder therebetween,said upper portion having a plurality of angularly spaced main portsextending therethrough adjacent but spaced above said shoulder, saidlower portion having a plurality of angularly spaced secondary portstherethrough adjacent but spaced below said shoulder, a generallytubular baffle received within said shell, said baflle having arelatively small diameter upper element received snugly within saidupper portion of said shell and having an annular upwardly facing edgegenerally at the level of the lower margins of said main ports, saidbaffle having an intermediate element spaced inwardly from said lowershell portion, said intermediate element defining an annular spacebetween said intermediate element said said lower shell portion, saidsecondary ports extending outwardly from said space, said baflle havinga lower relatively large diameter element snugly received within saidlower shell portion and spaced below said secondary ports, said bafliehaving a plurality of ports extending therethrough into said annularspace, a second battle of inverted cup-shape and having a top wallmounted on the underside of said top wall of said shell, said secondbafile having a generally cylindrical side wall depending from said topwall thereof and spaced radially inwardly from said upper portion ofsaid shell in coaxial relation thereto, the spacing between said baffleand said upper portion being a minor fraction of the diameter of saidbaffle said side wall of said second baflle having a lower annular edgegenerally at the level of said main ports to inhibit backfiringtherethrough.

4. In a burner, the combination comprising an outer sheet metal shellgenerally of inverted cup-shaped form and having an opening in its lowerend for receiving a mixture of fuel and air, said outer shell having atwodiarneter side wall surmounted by a flat horizontal top wall, saidside wall including a lower cylindrical relatively large diameterportion and an upper cylindrical relatively small diameter portion withan annular shoulder therebetween, said upper portion having a pluralityof horizontally alined radial main ports extending therethrough adjacentbut spaced above said shoulder, said lower portion having a plurality ofangularly spaced horizontally alined radial secondary ports therethroughadjacent but spaced below said shoulder, each of said secondary portsbeing substantially smaller than each main port, a generally tubularthree-diameter sheet metal baffle received Within said shell, saidbaffle having a relatively small diameter upper element received snuglywithin said upper portion of said shell and having an annular upwardlyfacing edge substantially at the level of the lower margins of said mainports, said baflie having an intermediate element of greater diameterthan said upper element but of less outer diameter than the innerdiameter of said lower shell portion, said intermediate element definingan annular space between said intermediate element and said lower shellportion, said secondary ports extending outwardly from said space, saidbafiie having a lower relatively large diameter element snugly receivedwithin said lower shell portion and substantially spaced below saidsecondary ports, said bafiie having a plurality of angularly spacedmetering ports extending through said intermediate element into saidannular space, a second inverted cup-shaped bafiie having a flat topwall mounted on the underside of said top wall of said shell, saidsecond baffle having a substantially cylindrical sidewall depending fromsaid top wall thereof and spaced radially inwardly from said upperportion of said shell in coaxial relation thereto, the Spacing betweensaid bathe and said upper portion being a minor fraction of the diameterof said bafile, said depending side wall having a lower annular edgesubstantially at the level of the axes of said main ports.

5. In a burner, the combination comprising a shell having an openingtherein for receiving a mixture of fuel and air, said shell having a topwall and a-generally cylindrical side wall extending downwardlytherefrom, a plurality of spaced generally circular ports extendingthrough said side wall and disposed therearound in a substantiallyhorizontal row, means inside said shell defining an annular ledgeextending inwardly from said side wall substantially at the level of thelower margins of said ports, and a depending baflle mounted on said topwall Within said shell and concentric with said side Wall, said bafileextending downwardly below the level of the upper margins of said portsand being closely spaced inwardly from said side wall by an amountcorresponding generally to the diameter of said ports so that saidbafile and said ledge will cooperate to prevent backfiring through saidports.

References Cited in the file of this patent UNITED STATES PATENTS365,606 Kline June 20, 1887 2,001,611 Ipold May 14, 1935 2,142,418Stocker Jan. 3, 1939 2,155,339 Stoll Apr. 18, 1939 2,215,176 ForsterSept. 17, 1940 2,220,247 Kochendorfer et al Nov. 5, 1940 FOREIGN PATENTS518,289 Germany Feb. 14, 1931

